Encoding 720p park_joy results in garbled decode.

Created by: gnafuthegreat

I encoded park_joy_420_720p50.y4m, and then decoded it using the specific git checkout of aom listed in the README. It resulted in this (after being piped to ffmpeg to dump PNGs):

https://themayhaks.com/~gideon/test-av1-png/

IVF file is here (about 88MB):

https://themayhaks.com/~gideon/test.ivf

I'm not sure if this is just a result of me not resizing to 1280x768 before feeding it to rav1e, but it didn't complain and it seems to have converted it to 1280x768 during the encoding process.